Effects of Different Probiotics on the Volatile Components of Fermented Coffee Were Analyzed Based on Headspace-Gas Chromatography-Ion Mobility Spectrometry

Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was used to study the effects of four kinds of probiotics on the volatile components of fermented coffee. The fingerprints showed that 51 compounds were confirmed and quantified, including 13 esters, 11 aldehydes, 9 alcohols, 6 ketones, 3 furans, 5 terpenes (hydrocarbons), 2 organic acids, 1 pyrazine, and 1 sulfur-containing compound. After fermenting, the aroma of the green beans increases while that of the roasted beans decreases. After roasting, the total amount of aroma components in coffee beans increased by 4.48-5.49 times. The aroma differences between fermented and untreated roasted beans were more significant than those between fermented and untreated green beans. HS-GC-IMS can distinguish the difference in coffee aroma, and each probiotic has a unique influence on the coffee aroma. Using probiotics to ferment coffee can significantly improve the aroma of coffee and provide certain application prospects for improving the quality of commercial coffee beans.

Effects of Three Extraction Methods on Avocado Oil Lipid Compounds Analyzed via UPLC-TOF-MS/MS with OPLS-DA

Avocado oil is excellent functional oil. Effects of three extraction methods (squeezing extraction, supercritical carbon dioxide extraction, and aqueous extraction) on the species, composition, and contents of lipids in avocado oil were analyzed via ultra-performance liquid chromatography–time-of-flight tandem mass spectrometry (UPLC-TOF-MS/MS), and the differential components of lipids were revealed by OrthogonalPartialLeast Squares-DiscriminantAnalysis (OPLS-DA), S-plot combined with variable importance in the projection (VIP). The results showed that the fatty acid composition of avocado oil mainly consisted of oleic acid (36–42%), palmitic acid (25–26%), linoleic acid (14–18%), and palmitoleic acid (10–12%). A total of 134 lipids were identified first from avocado oil, including 122 glycerides and 12 phospholipids, and the total number of carbon atoms contained in the fatty acid side chains of the lipids was 32–68, and the number of double bonds was 0–9. Forty-eight differential lipid compounds with significant effects of the three extraction methods on the lipid composition of avocado oil were excavated, among which the differences in triglycerides (TG), phosphatidylethanol (PEtOH), and phosphatidylmethanol (PMeOH) contents were highly significant, which provided basic data to support the subsequent guidance of avocado oil processing, quality evaluation, and functional studies.

Analysis of Physicochemical Properties, Lipid Composition, and Oxidative Stability of Cashew Nut Kernel Oil

Cashew nut kernel oil (CNKO) is an important oil source from tropical crops. The lipid species, composition, and relative content of CNKO were revealed using ultra high performance liquid chromatography time-of-flight tandem mass spectrometry (UPLC-TOF-MS/MS), and the physicochemical properties, functional group structure, and oxidation stability of CNKO at different pressing temperatures were characterized using a near infrared analyzer and other methods. The results showed that CNKO mainly consisted of oleic acid (60.87 ± 0.06%), linoleic acid (17.33 ± 0.28%), stearic acid (10.93 ± 0.31%), and palmitic acid (9.85 ± 0.04%), and a highly unsaturated fatty acid (78.46 ± 0.35%). In addition, 141 lipids, including 102 glycerides and 39 phospholipids, were identified in CNKO. The pressing temperature had a significant effect on the physicochemical properties of cashew kernels, such as acid value, iodine value, and peroxide value, but the change in value was small. The increase in pressing temperature did not lead to changes in the functional group structure of CNKO, but decreased the induction time of CNKO, resulting in a decrease in their oxidative stability. It provided basic data support to guide subsequent cashew kernel processing, quality evaluation, and functional studies.

Analysis of Lipids in Pitaya Seed Oil by Ultra-Performance Liquid Chromatography-Time-of-Flight Tandem Mass Spectrometry

Red pitaya (Hylocereus undatus) is an essential tropical fruit in China. To make more rational use of its processing, byproducts and fruit seeds, and the type, composition, and relative content of lipids in pitaya seed oil were analyzed by UPLC-TOF-MS/MS. The results showed that the main fatty acids in pitaya seed oil were linoleic acid 42.78%, oleic acid 27.29%, and palmitic acid 16.66%. The ratio of saturated fatty acids to unsaturated fatty acids to polyunsaturated fatty acids was close to 1:1.32:1.75. The mass spectrum behavior and fracture mechanism of four lipid components, TG 54:5|TG 18:1_18:2_18:2, were analyzed. In addition, lipids are an essential indicator for evaluating the quality of oils and fats, and 152 lipids were isolated and identified from pitaya seed oil for the first time, including 136 glycerides and 16 phospholipids. The main components of glyceride and phospholipids were triglycerides and phosphatidyl ethanol, providing essential data support for pitaya seed processing and functional product development.

Characterization of the volatile organic compounds produced from green coffee in different years by gas chromatography ion mobility spectrometry

The effect of storage time on green coffee volatile organic compounds (VOCs) was studied by their separation via head space solid-phase microextraction and identification via gas chromatography-ion mobility spectrometry. In total, 38 kinds of VOCs, mainly composed of alcohols, aldehydes, esters and ketones, were identified. The fingerprint showed that the VOCs produced by green coffee in different years had obvious differences, especially, acrolein, 3-methylbutyl acetate, butanoic acid, heptan-3-ol, and so on, that could be used to predict the storage time. In addition, with the increase of storage time, the contents of butanal, ethanol, dimethyl sulfide, propanal, butan-2-one had no obvious change, and could be considered as typical aroma characteristics of green coffee or special aroma components for variety identification. Meanwhile, principal component analysis (PCA) and "nearest neighbor" fingerprint analysis could also effectively distinguish green coffee with different storage times. Comprehensive analysis showed that GC-IMS technology could provide strong and favorable support for coffee storage.